Observations and results
Did the cup with the raw fruit remain a liquid? Did the cups with the cooked fruit and no fruit added solidify like normal?
Normally the collagen proteins in gelatin form a tangled mesh that traps water and other ingredients in it, giving the gelatin its semisolid form when it cools. Proteases can cut up the proteins so that the gelatin cannot solidify. There are several different kinds of proteases in the fruits recommended for this activity, and using any of these fresh fruits should result in gelatin that does not solidify well, if at all. Heating the fruit (through boiling or steaming), however, should inactivate the proteases, and the resulting gelatin mixture should solidify like normal (or nearly normal—if the fruit was hot when the gelatin was added, the solidified gelatin may have been slightly less firm than that in the cup without fruit). The proteases bromelain and papain (which come from pineapples and papayas, respectively) are often used in meat tenderizers. There are several other fruit proteases, however, such as actinidin (from kiwi fruit), ficin (figs) and zingibain (ginger).
You may enjoy a tasty fruit and gelatin dessert. Be sure to store it in the refrigerator until it is consumed.
More to explore
What Exactly Is JELL-O Made from? , from Discovery Communications, LLC
Science of fruit jellies , from The Naked Scientists: Kitchen Science
Enzymes Make the World Go 'Round , from Rader's Chem4Kids.com
Which Fruits Can Ruin Your Gelatin Dessert? , from Science Buddies
This activity brought to you in partnership with Science Buddies